Rotary compressor



ROTARY COMPRESSOR Fi;ed April 9, 193a a Sheets-Sheet 1 {kg Q 1 Q Q: Q

a; b W & Q N

Dec. 15, 1942. c. H. NICKELL 2,

ROTARY COMPRESSOR Filed April 9, 1938 mg Gum/M4 3 Sheets-Sheet 2 I w A IDec. 15, 1942. c. H. NICKELL ROTARY COMPRESSOR Filed April 9, 1938 3Sheets-Sheet 3 Patented Dec. 15, 1942 UNITED STATES PATENT OFFICE 2Claims.

This invention relates to compression apparatus and more particularly toa compressor of the rotary type.

, Prior to my invention it has been customary to utilize variousexpedients in the control of the capacity of compressors. In thoseinstallations where the compressor is driven by a motor operating atconstant or various speeds, and Where it is desired that the compressordeliver a constant pressure, it has been proposed that unloaderscomprisin spring pressed valves, be incorporated in a by-pass betweenthe discharge end of the compressor and its intake whereby when thecompressor is driven relatively fast, the compressor will be unloadedand excessive pressure avoided, and when the compressor is drivenrelatively slow or at a normal speed the by-pass will be closed and thecompressor will act at full capacity. This arrangement has been found tobe relatively inefiicient and excessive energy is required to drive thecompressor to effect the desired results, it being necessary for thecompressor to act against the spring operated valve at all times whenthe compressor is rotating at more than normal speed, at normal speed,or at less than normal speed.

It is the object of my invention to provide a simple, rugged,inexpensive, variable capacity rotary compressor for operation atconstant variable speed conditions.

It is a further object of my invention to provide a variable capacityrotary compressor of high efiiciency requiring a minimum of power underall conditions,

Other objects and the nature and advantages of the invention will beapparent from the following description taken in conjunction with theaccompanying drawings, wherein:

Fig. 1 is a view in cross section of a preferred form of my invention;

Fig. 2 is a sectional view taken along line 22 of Figure 1, looking inthe direction of the ar Referring to the drawings, the casting Ill com-55 prising the bearing support for my new compressor unit, is associatedat one of its ends with a supplementary casting I I which houses a pairof ball bearings I2 and I3 and a bellows type seal I4. At the other endof the casting Ill a bell shaped casing I5 is associated therewith andamong other functions attributed to it, houses the compressor cylinderI6 and end plate I'I.

Though the shaft I8 may be arranged to be directly driven by an electricmotor or other prime mover I have here shown a pulley l9 secured to theshaft I8, which pulley is adapted to be driven by a V belt which isassociated with the driving shaft of an electric motor or gasolineengine not shown. The bearing I3 and grease seal 20 are arranged toreceive lubricant from a source external to the system described in aconventional manner such as, for example, from a grease cup not shown.

To provide lubrication for the remaining parts, the lower portion of thebell casing I5 is supplied with oil when the compressor is first set upfor duty, which oil is arranged to be under the discharge pressure ofthe compressor and in normal operation is forced up through tube 2|through the center bore 22 of end plate II, then through the bore 23within the driven shaft 24, through metering plu 25, which permits onlya measured quantity of lubricant to pass therethrough, and then ontogears 26 and 21. By centrifugal force lubricant is thrown outwardly andsome of it passes through the openings 28 within gear 26 and is caughtin the depression 29 from whence it flows through bore 30 to the bellowsseal I4 and ball bearing I2, effecting lubrication of same. Theremainder of the oil which is not caught in crevice 29, falls to thesump 3| and collects therein until its level reaches the lower portionof suction tube 32, at which time it is sucked I I upwardly togetherwith the gas to be compressed which finds its way into chamber 33through inlet 34, to the suction side of the compressor 35 wherein gasis compressed and. is discharged together with lubricant to the chamber36 within the casing I5.

To insure thorough lubrication of the external surface of the drivenshaft 24 as it rotates within bearing 31 which may be made of bronze,Babbitt metal, or any suitable bearing material, a passage or bore 38 isarranged within the driven shaft 24 leading from the bore 23 to theexternal surface of the driven shaft 24, where by means of spiralgrooves 39, lubricant is conveyed to passages 40 thereby lubricating theexternal surface of the eccentric bushing member 4| which cooperateswith the internal surface of the casting H].

The compressor 35, shown in Figure 2, comprises a cylinder I6 and arotor element 42 cooperating therewith and provided with spring pressedvanes 43 which are urged outwardly to the inner surface of cylinder l6by springs 44. The cylinder 6 is provided with an inlet conduit 45 anda. discharge outlet 46, whereby when the rotor element 42 is rotated,gas to be compressed enters a space between the rotor element 42, thecylinder l6, and the two adjacent sliding vanes 43 and when the twomentioned sliding vanes are then rotated to a position adjacent the discharge passage 46, the gas is compressed and forced out of the cylinderHi. This action repeats itself and is continuous as long as the rotorrotates. When lubricant within the sump 3| reaches the bottom of thesuction tube 32, lubricant is sucked therethrough into the inlet conduit45 which leads to the compressor 35, as shown by the horizontal dottedlines in the upper central portion of Fig. 1. When the lubricant levelwithin the sump 3| is below the lower part of the suction tube 32, mererefrigerant to be compressed is sucked therethrough and reaches thecompressor 35 by means of the conduit 45. The discharge outlet 46communicates with the chamber 36, already referred to, permitting theoil to separate from the compressed gas and drop to the bottom of thecasing from whence it may be again picked up through the tube 2| andcirculated through the system. The released compressed gas then findsits way up into the dry pipe 41 through openings 48 in the bottomthereof, through check valve 49 to a place of use or a storage tank, notshown. While it is conceivable that the apparatus might be used as anair compressor, or other gas or liquid compressor or pump, it has beenespecially designed for use with volatile refrigerants, such as methylchloride, for example.

It is found in practice that in installations utilizing compressedgaseous fluid and incorporating continually operated compressors, forcertain periods at least, continued full load operation of thecompressor is unnecessary and wasteful of power. In the instantapparatus I have provided a control to affect the capacity ofthe'compressor, though continuously operating same, which comprises abellows 50, see Figure 3, one end of which is connected by a pipe 5| tothe discharge side of the compressor whereby the bellows is responsiveto the discharge pressure. with horizontally movable link 52, themovement of which toward the bellows 50 is to some extent controlled bythe position of the adjustable stop screw 53, to effect a predeterminedrelative position of the rotor 42 with respect to the cylinder I6, aswill be later described. Control of the movement of the bellows 50 iseffected by means of a spring 55 which directly engages the link 52 andis mounted within the casting ID for adjustment by means of knurledscrew 56 which is manually operable as shown in Figure 3, or may beautomatically controlled by means of a ther mostat (not shown) whicheiTects the compression of the spring 55 in accordance with thetemperature of the air cooled by an evaporator of a system incorporatingmy compressor as an element thereof. It is conceivable, of course, thatother automatic controls not shown might be utilized to effect thecompression of the spring 55.

This bellows 50 is operatively associated Horizontal movement of thelink 54 effects oscillation of the member 5'! with corresponding partialrotation of the eccentric bushing 4| which varies the location of thecenter of driven shaft 24, which in turn affects the capacity of theCompressor 35 by shifting the rotor 42 from the position shown in Figure4 to that shown in Figure 4a. This shifting of the rotor increases thevolume on the discharge side of the compressor thereby cutting downcompression and at the same time cutting down the energy required todrive the compressor under this varied location of the compressorelement 42 with respect t the cylinder l6.

This mode of operation of the control to affect the capacity of thecompressor is attributable to the contour and arrangement of theeccentric bushing element 4|.

To effect a similar result, that is, to vary the output of thecompressor in accordance with the pressure conditions within bellows 50,I may construct and arrange the eccentric bushing element Ma asillustrated in Figures 5 and 5a whereby when the member 51a isoscillated in response to pressure conditions, the rotor 42a is moveddirectly downwardly from its sealing position as illustrated in Figure 5to that shown in Figure 5a.

In a further modified form the output or capacity of the compressor isvaried in accordance with pressure conditions within the bellows 50 by aconstruction and arrangement of the eccentric bushing element 4|b asshown in Figures 6 and 6a. In this embodiment, upon oscillation of theelement 51b the driven shaft 24b is moved to a position such that therotor 42b is moved both down from its sealing position and also awayfrom same in a counter-clockwise direction to effect a position betweenthat illustrated in Figures 4a and 5a.

Though the driving shaft l8 transmits its motion through the medium ofgears 26 and 21, it is to be understood that I may utilize othertransmission means, such as for example, a pair of universal jointswhich will transmit rotation from the shaft l8 to the shaft 24, thoughthey are out of alignment. With the arrangement as illustrated in Figure1, however, positive driving means is effected in every position of theshaft 24 with respect to the shaft l8, and meshing engagement takesplace between a section of the teeth of gear 26 with the correspondingsection of the teeth of gear 2'! though these sections vary with theposition of the eccentric bushing 4|, which in turn is controlled by thepressure within the bellows 50 and may be modified by an adjustment ofthe compression of the spring 55 either manually, as by adjustment ofknurled screw 56, or by automatic means not shown but described.

It will be seen from the above disclosure that the compression apparatusdescribed is capable of efiicient operation under many varyingconditions and produces desired results. In practise it has been foundthat when the compression apparatus is driven at various speeds rangingfrom as low as 200 R. P. M. or even lower, to as high as 6000 R. P. M.or even higher, a substantially constant pressure was evolved with theexpenditure of a minimum of energy, the controls effecting the desiredrelation between the rotor and the cylinder. These characteristics areespecially desirable when the compression apparatus is associateddirectly with an internal combustion engine, such as, for example, the

motor of a conventional automobile. Though, of course, the samecharacteristics are particularly desirable when the apparatus isassociated with other drives, such as, for example, constant speedengines or continuously operating motors.

The construction of my device is found to be advantageous in that theparts are especially rugged and so associated with each other undervarying conditions of control as to make for a minimum of wear of movingparts. This last mentioned advantage may, in part, be attributed to theparticularly desirable lubricating system inherent in the design of theapparatus. Not only is the apparatus efficient and long lived, but itrequires a minimum of attention during operation, the controls beingwithin the apparatus and automatic.

Under different conditions of duty, various cooling means may beassociated with the compression apparatus such as, for example, systemsinvolving cooling water, volatile refrigerants, or merely fins aboutwhich air may be arranged to pass.

It will be obvious to those skilled in the art that various changes maybe made in this device without departing from the spirit of theinvention and therefore the invention is not limited to what is shown inthe drawings and described in the specification but only as indicated inthe appended claims.

I claim:

1. In a compression apparatus, a rigid nonjointed driving shaft and arigid non-jointed driven shaft, means for effecting relative movement ofsaid shafts in a direction perpendicular to their axes to aifect thecapacity of said apparatus, continuous transmission means between saidshafts comprising a pair of multi-position engaging gears, one of whichbeing associated with said driving shaft and the other of which beingassociated with the driven shaft, a compressor including a cylinder anda compression element operatively mounted in said cylinder and driven bysaid driven shaft, said compressor also including an oil reservoir,means for subjecting said reservoir to compressor discharge pressure,oil conduit means connecting said oil reservoir with said transmissionmeans, a bearing and a seal associated with said driving shaft, andmeans responsive to operation of said transmission means for effectingtransfer of said oil from said reservoir to portions of saidtransmission means, said bearing, and said seal.

2. In a compression apparatus, a rigid nonjointed driving shaft and arigid non-jointed driven shaft, a rotary piston mounted on said drivenshaft, a stationary cylinder about said piston, transmission meansbetween said shafts comprising a pair of multi-position engaging gears,one of which being associated with said driving shaft and the other ofwhich being associated with said driven shaft, said compressionapparatus including an oil reservoir, a bearing and seal associated withsaid driving shaft, means for subjecting said oil reservoir tocompressor discharge pressure, conduit means connecting said oilreservoir to the exterior of said driven shaft and portions of saidtransmission means, passage means adjacent said transmission means forreceiving oil therefrom and conducting oil to said bearing and saidseal, means for returning excess lubricant from said transmission meansto said oil reservoir, means for varying the position of the axis of thedriven shaft to affect the capacity of said compressor andsimultaneously change the position of engagement of said gears withinsaid transmission.

CLAUDE H. NICKELL.

